Sequence and Relationships of Sugarcane Mosaic and Sorghum Mosaic Virus Strains and Development of RT-PCR-Based RFLPs for Strain Discrimination

ABSTRACT Sugarcane mosaic is the most widespread virus disease affecting sugarcane production. We have established a collection of seven prominent sugarcane mosaic potyvirus (SCMV) strains currently causing disease in sugarcane throughout the world and originally found in sugarcane in the United States. This collection includes SCMV strains A, B, D, and E, and the sorghum mosaic virus (SrMV) strains SCH, SCI, and SCM. These viruses were propagated on Sorghum bicolor cv. Rio and purified. Cloned cDNAs representing 2.0 kb of the 3′ termini, obtained after a reversetranscriptase-polymerase chain reaction (RT-PCR) on purified virions using an oligo(dT) primer and degenerate primers with sequences located in the NIb gene, have been sequenced for each of these strains. A comparative analysis of the deduced amino acid sequences in the NIb and coat protein genes and of the nucleotide sequences in the 3′-untranslated region, among these seven viruses and among six other members of the SCMV subgroup, confirms that ...